Airplane-control-surface rib connection



A. K. LONGREN AIRPLANE CONTROL SURFACE RIB CONNECTION June 17 1924.

2 Sheets-Sheet 1 Filed Sept. 1, 1922 I I A TTORNE Y June 17, 1924. 1,498,050

A. K. LONGREN AIRPLANE CONTROL SURFACE RIB CONNECTION Filed Sept. 1, 1922 2 Sheets-Shea. 2

. INF/INTO]? 8 7/007 ff [0/75/07 A 770mm 7 Patented June 17, 1924.

UNITED STATES PATENT OFFICE.

ALBIN' K. LO'NGREN, OF TOPEKA, KANSAS.

AIRPLANE-CONTROL-SURFACE RIB CONNECTION.

Application filed September 1, 1922. Serial No. 585,682.

To all whom it may concern.

Be it known that I, ALBIN K. LONGREN,

a citizen of the United States, residing at Topeka, in the county of Shawnee and State of Kansas, have invented certain new and useful Improvements in Airplane-Control-Surface Rib Connection; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

This invention refers to means for connecting the ribs to thehinge tube in any of thecontrol surfaces of an airplane, such as the elevators, rudders, or ailerons, and the invention particularly contemplates the kind of screws used and the manner of their application in order to influence the tension of the metal straps used in attaching the wooden ribs to the metallichinge tube.

The novel means by which these screws are introduced into the part which they engage in order to insure the necessary tightness or tension in the metal straps will be particularly referred to hereinafter, reference being made to the accompanying drawings, in which Fig. 1 is a perspective view of the tail end of an airplane constructed in accordance with my invention.

Fig. 2 is a transverse sectional view through the tail end of the fuselage, show ing the elevator control arms and the elevator hinge tube in elevation.

Fig. 3 is a fragmentary view, partly in section, showing one of the ribs.

Fig. 4: is a similar view showing the metal hinge tube and the metal strap for securing the ribs thereto, the tensioning screw being in position to enter its opening, and

Fig. 5 is a fragmentary perspective view of an elevator frame.

For the purpose of illustration I will describe in detail the construction of the elevators, it being distinctly understood that precisely this same method of construction applies to the ailerons, and rudders as well as to the elevators.

Referring now to the drawings by numerals of reference:

1 designates the tail end of a fuselage pro- Vided with horizontal stationary surfaces or stabilizers 2 and 3, and a vertical stationary surface or fin ,4.

The elevator is built up on a metal tube 8-the hinge tubewhich forms the for ward edge of said control surface. The 0pposite, or trailing edge,and the ends are formed by a smaller. metal tube 10, 11, and 12, bent and attached to the ends of the hinge tube as shown in Fig. I

The rectangular frame thus formed is filledin with numerous wooden ribs 13, suitably slotted at 14 for lightening purposes. A brace 22 may connect the smaller metal tube parts 11 and 12, same passing through the slots 14 of the ribs 13 as clearly shown inFig. 1. The rear end of'each rib is out or notched, as at 15, to fit the curve of the trailing edge tube 10, and the forward end of each is rounded out as at 16 to fit the curve of the hinge tube 8.

The ribs 13 are rigidly fastened to the hinge tube 8 .by means of metal straps 17, which pass around the hinge tube 8 and have their ends secured to the ribs 13 by means of screws 18 and 19.

In order to provide for the maximum strength and to preventthe rib from split ting, I bore two holes 20 and 21 in the end of the rib 13. These holes are drilled slight ly less in diameter than the diameter of the screws 18 and 19. I prefer to use machine screws because in actual. practice, I have found that they afford the most secure means for fastening the straps. By offsetting the holes 20 and 21 there is very little chance of the ribs being split by the screws 18 and 19, as would be the case if the holes were in alignment and gave one continuous hole entirely through the rib.

In fastening the rib to the hinge tube 8 I prefer to first attach one end of the metal strap 17 to the rib by means of the screw 18; the other screw 19 is then inserted in the hole in the other end of the strap 17 with its point projecting throughslightly. The strap 17 is then bent around the hinge tube 8 and the point of the screw 19 inserted in the hole 21, as shown in Fig. 4. When the screw 19 has been given a few turns to get it firmly started in the hole 21 it is then straightened up until its axis is in actual alignment with the axis of the hole 21. Theproper length for the strap 17 having been previously calculated provides that this straightening of the screw 19 will place the proper tension in the metal strap 17 for the making of a tight connection between the rib l3 and the hinge tube 8 The strap 17 is then to be attached to the hinge tube 8 by means of rivets or screws, brazing or spot 'weldingeither'elec-' tric or autogenous, as shown at 31. M

This work of assembling can be done by inexperienced workmen and in actual practice I have found that this simple and inexpensive method greatly reduces the ultimate cost of the airplane."

What I claim and ters-Pateiit is: p r a c l. A control surface rib connection for airplanes comprising a frame having a metal hinge tube forming one side thereof, a plu rality of wooden ribs at right angles to said hinge tube, metal straps passing around said hinge tub,e, and screws offset one with the other and fastening the's'tiaps to, the ribs the operative positioning of the last-screw tensioning the strap for the making of a tight, connection between the strap ,and hinge 1 tube. v

2. A control surface rib connection "for airplanes comprising a frame including a metal hinge tube at its forward or leading edge, a smaller metal tube for its rear or trailing edge, having end portions connecting withthe hinge tube slotted, wooden ribs extending transversely of the frame and having their ends cut or notched in order to fit the hinge tube and the trailing edge of the smaller tube, metal straps passing around the hinge tubes, a bracing element passing desire t5 secure By Lathrough the'slots of the wooden ribs and connecting the end portions of the trailing tube and means for attaching the ends of the straps to the ribs comprising'screws received in olfset openings in the ribs, the screws exerting tension on the straps.

3. A control surface rib for airplanes comprising an elongated wooden member having a longitudinal slot therein to reduce weight,

the respective ends of the member being spective ends of the member being notched to engage bars of a supporting frame,- one end of the member being larger than the other, the larger end being, provided with two offset screw holes on opposite sides, :1 metal-strap for securing one end of the rib to its support, and machine screws passing through the ends of the metal strap and engaging offset screw holes in the rib.

5. A control surface rib for airplanes comprising an open frame, including a hinge tube, a plurality of wooden ribs mounted in the frame at right angles to the hinge tube and each having a notch embracing the inner side of the hinge tube, a metal strap connected at one end to each rib and passing around and embracing the outer side of said hinge tube and at its opposite end connected to the respective ribs, the devices for connecting the endsof the straps to the respec tive ribs entering the latter in opposite directions and in spaced overlapping relation adjacent the hinge tube.

, In testimony whereof I aflix my signature.

ALBIN K. LONGREN. 

